1. Field of the Invention
This invention relates to large capacity 2 wire core memories and more particularly to such memories which internally perform serial data cycles with overlapping drive currents and which have shared drive circuitry.
2. Description of the Prior Art
Two wire, 21/2D core memories utilize two oppositely oriented cores for each intersection of an X current and a Y current pair. The direction and relative polarities of the three partial select currents determine which of the two cores is selected and the polarity of the resulting EMF switching force. The X current adds to a Y current at the selected core and cancels the other Y current at the unselected core of an oppositely oriented core pair.
Two wire, 2D memories have the advantage of reducing stack wiring costs in comparison to three wire, 3D memories, but this advantage is typically overshadowed by increased costs for current matrix and sense circuitry. The 21/2D memory organization helps to reduce the cost of the electronics relative to 2D memory configurations but heretofore has not been sufficient to make the arrangement competitive with three wire 3D arrangements.